This invention relates to a method and apparatus for cutting and chopping brush and of containing ground fires.
Ground fires consume millions of acres of wilderness annually. In 1999, the National Interagency Fire Center reported that over five million acres of land were burnt and that the federal government spent over a half billion dollars to suppress wilderness fires. In 2000, over 6.3 million acres of wilderness h have been burnt and the U.S. Congress has budgeted 638 million dollars to cover the direct cost incurred suppressing and ground fires, and the total cost is expected to exceed 1 billion dollars in 2000.
Typically, brush, which includes bushes, vines, small trees and other low to midheight vegetation, is the fuel source of ground fires. Large trees usually are resistant to low lying ground fires, provided the ground fire is not hot enough to ignite the canopy of the large tree. When the ground vegetation is dry, as frequently happens during the summer months, ground fires are capable of burning extremely hot and fast.
Firebreaks are generally made by either ground crews using axes, hoes, and other equipment, to manually remove brush, or by mechanical means such as a tractor or a bulldozer. When a tractor is used to create a firebreak, the tractor pulls a plow through the brush and the ground in which the brush is growing, and the surface earth and the brush are turned over so that the brush becomes substantially covered by a layer of dirt. Thus, when a ground fire reaches the firebreak, the combustible material, the foliage of the brush, is essentially buried and the fire is contained by the firebreak. Bulldozers are used in a similar manner to create firebreaks. A bulldozer with an attached blade uses the blade to simply scrape away a portion of the topsoil and the brush growing in the ground as the bulldozer moves forward. In its wake, the bulldozer leaves a strip of land devoid of brush, so that a ground fire is contained by the firebreak.
While firebreaks are generally effective in containing ground fires there are problems associated with them. For example, because firebreaks are essentially bare ground devoid of vegetation they are prone to water erosion, thereby polluting nearby streams, creeks, rivers, etc. and causing other environmental damage associated with water erosion. In addition, it is not easy or quick to make a firebreak, whether it is made manually or by mechanical means, such as by a tractor. Depending upon the terrain, it may take a tractor an hour to create a xc2xe of a mile firebreak. In addition to being slow, tractors and bulldozers generally are heavy pieces of equipment that are not easily transported from a central location to an area in which it is desired to build a firebreak in the path of a fire. Therefore, there is a need for an apparatus and a method for containing ground fires and for addressing these and other related problems.
Briefly described, the present invention comprises a method and an improved apparatus for cutting and chopping low to mid height vegetation, referred to as brush, and forming breaks in the brush for suppressing and containing ground fires. A ground fire can be contained and suppressed behind a strip of land in which bushes, brush, small trees, and other vegetation growing in the strip of land have been transformed from its natural state into generally particles disposed substantially flat on the ground. The brush, when cut and chopped, tends to lie low on the ground, and the low lying chopped vegetation does not lie high enough from the ground to provide air space between the cut chopped vegetation and the ground to allow a flow of air and its oxygen to support combustion of or leaping flames from the chopped vegetation. To form brush into chopped vegetation, a self propelled apparatus is guided, or driven, through the brush. As the apparatus moves forward it engages brush in its path, and the apparatus has a cutting means that cuts the engaged brush proximal to the ground. The cut brush is urged inwardly toward the center of the apparatus by the cutting means and is re-cut as the apparatus moves forward. The re-cut pieces are generally particles that are deposited on and lay substantially flat on the ground. The root system of the cut brush remains essentially undisturbed by the apparatus. The strip of land having the brush cut and chopped is for the purposes of this disclosure known as a fuelbreak. For the purposes of this disclosure, the chopped vegetation is vegetation that has been cut from the ground and re-cut into pieces that lay generally flat on the ground. The chopped vegetation is of varying size and shape depending upon both the type of vegetation and the part of the vegetation that the apparatus has chopped. Generally, as will be described in greater detail herein below, chopped pieces can be small pieces such as twigs, leaves, grasses, etc., or large pieces such as tree trunks, branches, limbs, etc. The large pieces, such as a tree trunk, are cut in such a manner that branches growing from the trunk are chopped off of the trunk so that the trunk will lie flat on the ground. Similarly, branches having smaller branches growing therefrom are cut so that the smaller branches are generally chopped therefrom so that the branch will lie flat on the ground. Thus, the fuelbreak is typically covered by chopped vegetation that includes both small and large particles.
Even though a fuelbreak is not devoid of vegetation, as a firebreak might be, a fire is easily contained by fire fighters behind a fuelbreak. Because the fuel source, the vegetation, in a fuelbreak has been cut and re-cut so that it lies substantially flat on the ground, air does not easily reach the re-cut vegetation when it is ignited. Thus, a fire might not occur in a fuel break, or when a fire reaches a fuelbreak and ignites the chopped vegetation, the fire generally is transformed from a fast moving, hot burning fire into a cooler smoldering fire that is easily extinguished by fire fighters.
A fuelbreak has advantages over firebreaks for containing ground fires. One advantage of a fuelbreak is that the roots of the cut vegetation remain substantially undisturbed during the process of making the fuelbreak. Thus, with the root system of the cut vegetation intact, a fuelbreak is not prone to water erosion because the roots stabilize the ground, thereby mitigating the harmful effects to the environment associated with a firebreak.
In addition, when a firebreak is made in soft, loose, sandy soil, such as sugar sand, the firebreak is generally impassable to subsequent vehicles. Whereas, with a fuelbreak the ground has not been plowed, or scraped, and consequently, the ground which is stabilized by the roots of the cut vegetation and covered by a layer of the cut vegetation is generally firm enough to support subsequent vehicles. The cut brush forms a blanket, or layer, of tractionable material that helps prevent a subsequent vehicle from becoming stuck in the loose sandy soil, or sugar sand. Other features and advantages of a fuelbreak will be discussed in greater detail hereinbelow.
In the preferred embodiment of the invention, the apparatus for making a fuelbreak is a ground clearing cutter which includes a rear mounted skid steer riding tractor, described in greater detail hereinbelow. The preferred apparatus is a distinct improvement over bulldozers and tractors that pull a plow for an apparatus used in containing ground fires. Frequently, a ground fire will occur in a remote region, and fire fighting equipment and personnel must be transported to the remote region to combat the ground fire. In comparison to bulldozers and tractors having a plow, the preferred apparatus is generally light weight and is easily and rapidly transported on a small truck, or a small trailer pulled by vehicle such as a pickup truck, from a central location to the remote region for deployment against the ground fire, whereas a bulldozer, for example, is normally transported on a large flat bed behind a semi-truck. Therefore, when time is of the essence, as is normally the case when fighting fires, the preferred apparatus can be deployed from a central location faster then conventional bulldozers and tractors.
Another advantage of the preferred apparatus is the speed of the apparatus. Depending upon the terrain, the preferred apparatus can generally make a 1xc2xd mile fuelbreak in an hour, whereas, a tractor pulling a plow over the same terrain will normally make a xc2xe of a mile fuelbreak in the same time. The preferred apparatus is capable of speeds greater than 1xc2xd miles/hour and is generally twice as fast, or faster, than a tractor.
In addition to making a fuelbreak for containing a fire the preferred apparatus can be used for suppressing ground fires. Typically, it is the undergrowth vegetation or brush that initially spreads a ground fire in a woodlands area. By rendering the brush from its natural state into pieces that lay generally flat on the ground a fire is likely to be contained to a few trees. The preferred apparatus is highly maneuverable, much more so than bulldozers or tractors, so that it can be maneuvered around large trees, boulders, etc. and other obstacles found in woodlands areas. Thus, it is used for cutting and chopping the undergrowth vegetation found in woodlands areas to help prevent the occurrence of forest fires.
In the preferred embodiment, the self propelled apparatus comprises an improved ground clearing brush cutter which includes a skid steer tractor with a front mounted cutter assembly which is rigidly mounted to the tractor while being allowed to pivot with respect to the tractor about a longitudinal axis. The cutter assembly includes its own castor wheels that adjustably support the cutter assembly from the surface of the ground so as to change the height of the cutter assembly from the ground. The castor wheels are of rugged construction so as to withstand impact from trees and obstacles, which is not required by grass cutting equipment.
The cutter assembly includes a cutter deck, at least two outboard rectilinear rotary cutter blades suspended beneath the cutter deck that straddle the centerline of the cutter assembly, and a hydraulic motor for each of the cutters. Each hydraulic motor drives one of the outboard rectilinear rotary cutter blades so that the at least two outboard rectilinear rotary cutter blades are driven in opposite, counter-rotation directions. The counter rotation of the cutter blades results in the directions of movement of the blades at the front of the cutter deck moving in arcs inwardly and toward the centerline of the apparatus and then rearwardly of the apparatus. This cuts the brush in the cutting path with a motion that urges the cut brush inwardly between the blades and rearwardly beneath the cutter deck, causing the brush to be cut and re-cut as it passes beneath the cutter deck. This multiple cutting of the brush results in smaller pieces of the brush being deposited on the ground in the path of the apparatus.
The mid to large sized brush, including young trees, is pushed over by the leading portion of the cutter assembly and has the tendency to fall forwardly with respect to the implement after it has been initially cut, into the cutting path, where the brush will be overrun by the brush cutter and be re-cut. This is accomplished by placement of a leading portion of the cutter assembly forwardly of cutter blades along the cutting path. The counter direction of rotation of the blades, whereby the leading arcs of the blades rotate inwardly toward the centerline of the cutter assembly, causes the initially cut brush, etc. which is being overrun by the cutter assembly to be drawn between the blades and beneath the cutter deck where it is chopped and discharged rearwardly of the cutter assembly. Portions of the initially cut brush that extend beyond a given height from the ground are chopped off of the initially cut brush as the brush cutter advances over the initially cut brush. The chopping off of the protruding portions causes the initially cut portion to churn, or spin, thereby exposing other portions that were initially on the ground to the cutting blades so that they are then chopped off of the initially cut brush. Thus, the initially cut brush lies generally flat on the ground when the protruding portions of the brush have been cut off of the initially cut brush. Similarly, chopped off portions lying on the ground that extend beyond the given height are re-chopped by the cutting blades so that the chopped off portions lay generally flat on the ground.
The height of the cutter deck from the ground can be adjusted without disturbing the vertical position of the castor axle with respect to the axle housing. In the embodiment disclosed herein the castor wheels are mounted to a U-shaped castor shaft support, and the shaft support is, in turn, supported by an upright support or housing connected to a way mounted to the cutter deck. When the height of the cutter deck and cutter blades is to be changed, the castor shaft support or housing is adjusted with respect to the cutter deck through the adjustability of its support ways, thereby effectively adjusting the relative vertical position of the castor wheels with respect to the cutter assembly.
Because of the multiple cutting of the brush by the cutter blades beneath the cuter deck, more power is required by the cutter blades to adequately chop the brush. In the preferred embodiment of the invention, the cutter blades are each individually powered by a hydraulic motor and a short connector belt from the motor to the spindle of the cutter blade, instead of by long belt drives. This avoids belt slippage and belt wear, avoids having to arrange for a twisted belt arrangement to reverse the rotation of the outboard blades, and assures having enough power to perform proper chopping of the brush with one pass of the implement.
Thus, it is an object of this invention to provide an improved brush cutter that includes a skid steer tractor with a front mounted cutter assembly, which operates to cut and chop brush including young trees and other mid-sized vegetation, without requiring the implement to be moved over the brush a second time to achieve laying the chopped vegetation generally flat on the ground.
Another object of the present invention is to make a fuelbreak by using an improved brush cutter that cuts and chops brush and disposes the chopped brush generally on the ground.
Another object of this invention is to create a fuelbreak in which the root system of the cut brush is left substantially intact, thereby creating an environmentally benign means of containing a ground fire.
Another object of this invention is to dispose of the chopped brush on the ground substantially along the path traveled by the improved brush cutter.
Another object of this invention is to create a fuelbreak that is passable to subsequent vehicles.
Another object of this invention is to cut and chop brush in woodland areas for suppressing the occurrence of fires.
Another object of this invention is to provide an improved brush cutter for clearing land of the foliage of the brush, of the type that includes a rear mounted tractor, a front mounted cutter assembly, and with the chassis of the tractor and the cutter deck of the cutter assembly tiltably mounted to one another about a longitudinal axis, with the cutter assembly structured to engage and bend the brush in the direction of advancement of the implement along the cutting path as the base of the brush is first cut by the cutter blades, and with the cutter blades positioned and operable to overrun the initially cut brush and re-cut the brush and to urge the cut brush to move between the cutter blades and rearwardly from the cutter deck.
Another object of this invention is to provide a brush cutter that engages brush and bends it over in preparation for cutting, and after the vegetation is cut it falls in the path of the oncoming cutter therefore causing the brush to be re-cut.
Another object of the invention is to provide a brush cutter that provides for outboard blades, which rotate inwardly to draw brush toward the centerline of the cutter deck where the brush is re-cut and chopped.
Another object of the invention is to provide a brush cutter that provides for outboard blades driven by hydraulic motors, which rotate inwardly to draw the cut brush toward the centerline of the cutter deck where the cut brush is re-cut and chopped.